The present invention relates to bicycle rear-wheel hub assembly which is durable in use and can eliminate noise while changing the position of the bicycle chain.
Several flywheels may be simultaneously attached to a bicycle's rear-wheel hub for mounting the chain alternatively so that the speed of the bicycle can be changed. In regular speed changing bicycles, the smallest flywheel has total 14 teeth. Because of the number of teeth on the smallest flywheel is limited to 14 teeth, the speed of a speed changing bicycle can not be greatly improved. Further, because the tooth forms of the flywheels of a speed changing bicycle are not variable (see FIGS. 1 and 2), noise and friction problems will happen while changing the position of the chain, causing the chain to disconnect from place.